February 15, 2011
The recently published Ontario Guidelines for Residential Rainwater Harvesting (RWH) Systems are the first of its kind in the province.

The four-year project involved researchers from the University of Guelph, Ontario Ministry of Municipal Affairs and Housing, Connect the Drops and members of the Province’s private sector.

The guidelines cover a variety of topics, including the sizing of rainwater storage tanks, installation of rainwater (non-potable water) plumbing, rainwater treatment, as well as how to design RWH systems to operate during dry periods and handle overflows from the tank. The document focuses upon residential applications, but is also a valuable tool to assist with the design, installation and management of RWH systems in industrial, commercial and institutional buildings.

Chris Le Conte, former chair of LO’s Irrigation Sector Group, said, “The sector group did have contribution to these standards, via my involvement in the stakeholder consultation sessions. I feel these guidelines are a step forward and should be looked at as another tool that the landscape industry can use to help their clients manage water wisely.”

Rainwater Harvesting (RWH), the ancient practice of collecting rainwater and storing it for later use, is gaining in popularity. Research conducted by the Toronto and Region Conservation Authority (TRCA), through the Sustainable Technologies Evaluation Program (STEP), showed that RWH systems in commercial and industrial buildings can lower annual water use for toilet flushing and grounds irrigation between 59 and 76 per cent.

In a study of rainwater harvesting in suburban homes, the University of Guelph reported savings of 60,000 to 70,000 litres of water annually.  

The guidelines are available to download for free at www.sustainabletechnologies.ca.